The present invention relates to a technique and an equipment for the thermoelectric cooling, in particular, to a heat conducting and dispersing equipment used in the thermoelectric cooling device.
The thermoelectric cooling is a benefit of the so-called Peltier effect which utilizes the potential change of the electrons and the holes in a circuit including two dissimilar conductors, and the phenomenon of the heat absorption and discharge which produces a hot end and a cold end, to perform cooling (or heating) functions. Since there is a current flowing through the thermocouple during operation of the cooler, the Joule heats will be created, at the same time, the temperature at the hot end tends to expand to the cold end, thus at a thermal equilibrium situation, the equilibrium equation will be as follows:
Qc=apnTcIxe2x88x920.5I2Rxe2x88x92K(Tnxe2x88x92Tc)
That is, the amount of cooling at the cold end is equal to the Peltier cooling effect subtracted by a half of the Joule heat carried to the cold end, then subtracted by the heat transferred from the hot end to the cold end according to Fourier Heat Conducting Rule. It can also be derived from the above equation that, in case of not changing the materials of the thermocouple and the means for heat conducting and dispersing, both the cooling effect and the cooling efficiency tend to be zero when the temperature difference between the cold end and the hot end is the maximum. Therefore, in order to enhance the cooling efficiency, in addition to select a proper working current and a power for minimizing the Joule heat carried into the cold end, the most important fact for accessing the maximum cooling effect is to improve the means for heat conducting and dispersing in the thermoelectric cooling components, to minimize the heat exchange produced by the heat accumulation on both the ends and to reduce the temperature difference between the two ends. Therefore, the development of a high efficient heat conducting and dispersing equipment is very important for improving the operation condition of the thermoelectric cooling device, enhancing the cooling efficiency, enlarging the cooling volume, and obtaining a broader application, etc.
The thermoelectric cooling device used frequently in the recent years is composed of three components: a thermoelectric cooling member, a cooling transmitting member and a hot-end heat dispersing member. The thermoelectric cooling member is generally made of the semi-conducting materials. The cooling transmitting member uses a rib radiator or a large area metal plate. The hot-end heat dispersing member can be cooled by several means such as free cooling by a radiator, enforced cooling by a fan, free cooling by an internal water circulation, enforced cooling by an external water circulation, and heat absorbing by other materials, etc. For example, a room refrigerator shown in FIG. 1 uses a rib radiator; a vehicle-carried refrigerator shown in FIG. 2 uses a large area metal plate as the heat conductor at the cold end and a round needle-like radiator at the hot end; a refrigerator shown in FIG. 3 uses a rib radiator at the cold end and an internal free water circulation at the hot end; a refrigerator shown in FIG. 4 uses a round needle-like radiator at the cold end and an enforced external cooling water circulation at the hot end. In FIG. 1-4, the reference sign H, C and F are used to represent the heating space, the cooling space of cold end, and the fan, respectively. It is known from a long period of research and development that the heat conducting and dispersing member made of a kind of metal (FIGS. 1 and 2 ) has a heat exchange coefficient of only 3xcx9c8 w/(m2k),and of 26-30 w/(m2k) in the case of enforcet cooling with associated fans. Because of having heat resistance, the efficient heat conducting area is limited within a circle centered at the hot source and having a radius of 150 mm-180 mm. Outside this area, the heat conducting capability reduces significantly. For an internal water circulation (FIG. 3), the heat exchange coefficient can be as high as 110-170 w/(m2k), however, it needs a relatively large circulation volume to perform the heat exchange with the environment. Thus, it is difficult to manufacture and easy to get leaking and corrosion during the installation. For an external water circulation (FIG. 4), the inlet and outlet of the water circulation for heat discharging are connected to a pressurized water supply and the heat is brought out by the external water circulation. The heat exchange coefficient of this type can be as high as 150-1000 w/(m2k), however, a corresponding water supply and a water pump is necessary, the application is thus limited. In a heat dispersing member that utilizes principle of the heat from melting, the heat from solving and heat capacity of the materials, the disadvantages are resulted from the corrosion of the conducting components, the non-continuity and the instability of the heat discharging therefore, this type of the heat dispersing is not used widely. For all above mentioned reason, it is a urgent subject to develop a high efficient heat conducting and dispersing device in the thermoelectric cooling technology.
An object of the present invention is to provide a thermoelectric cooling device that uses a heat pipe to conduct and disperse heat and applies evaporation and condensation (phase change) to absorb and discharge heat, so that achieves a high efficient and large area heat conduction and dispersion.
The object of the present invention can be realized with a thermoelectric cooling device used for various of the thermoelectric cooling apparatus and products. It uses a heat pipe as the heat conducting and dispersing means. It comprises: (1) a thermoelectric cooling member being composed of a cold and a hot ends; (2) a cooling transmission member being composed of a trapezoidal condenser attached to the cold end of the thermoelectric cooling member and a multi-bundle of the heat pipe conductors arranged between the trapezoidal condenser and the cooling space; (3) a heat dispersing member at the hot end, comprising a trapezoidal evaporator attached to the hot end of the thermoelectric cooling member, and a multi-bundle of the heat pipe radiators arranged between the trapezoidal evaporator and the heat dispersing space; (4) a phase-changeable working medium filled into above-mentioned cooling transmission member and the hot-end heat dispersing member.
In the most preferred embodiment, said multi-bundle of the heat pipes form a closed circulation with the trapezoidal condenser and the trapezoidal evaporator respectively, the working medium flows in this circulation. That is, in the cooling transmission member, each heat pipe extends upwardly from the top end of the trapezoidal condenser, passing the cooling space, and connects downwardly to the bottom end of the trapezoidal condenser; while in the hot-end heat dispersing member, each heat pipe extends upwardly from the top end of the trapezoidal evaporator, passing through the heat dispersing space, and connects downwardly to the bottom end of the trapezoidal evaporator.